[0/5] LSM: Measure security module state

Message

Lakshmi Ramasubramanian June 13, 2020, 2:41 a.m. UTC

Critical data structures of security modules are currently not measured.
Therefore an attestation service, for instance, would not be able to
attest whether security modules are always operating with the policies
and configuration that the system administrator had setup. The policies
and configuration for the security modules could be tampered with by
malware by exploiting Kernel vulnerabilities or modified through some
inadvertent actions on the system. Measuring such critical data would
enable an attestation service to better assess the state of the system.

IMA measures system files, command line arguments passed to kexec,
boot aggregate, keys, etc. It can be used to measure critical
data structures of security modules as well.

This change aims to address measuring critical data structures
of security modules when they are initialized, when they are updated
at runtime, and also periodically to detect any tampering.

This change set is based off of Linux Kernel version 5.8-rc1

Lakshmi Ramasubramanian (5):
  IMA: Add LSM_STATE func to measure LSM data
  IMA: Define an IMA hook to measure LSM data
  LSM: Add security_state function pointer in lsm_info struct
  LSM: Define SELinux function to measure security state
  LSM: Define workqueue for measuring security module state

 Documentation/ABI/testing/ima_policy |  6 +-
 include/linux/ima.h                  |  4 ++
 include/linux/lsm_hooks.h            |  5 ++
 security/integrity/ima/ima.h         |  1 +
 security/integrity/ima/ima_api.c     |  2 +-
 security/integrity/ima/ima_main.c    | 30 +++++++++
 security/integrity/ima/ima_policy.c  | 28 +++++++--
 security/security.c                  | 91 +++++++++++++++++++++++++++-
 security/selinux/hooks.c             | 43 +++++++++++++
 security/selinux/include/security.h  |  2 +
 security/selinux/selinuxfs.c         |  1 +
 11 files changed, 205 insertions(+), 8 deletions(-)